1. Field of the Invention
The present invention relates to an engine output control device for vehicles that controls the engine output by controlling the position of the rack in the fuel injection system.
2. Related Art
The traction control systems provided in vehicles today detect the amount of slippage between the drive wheel and the slave wheel and if the amount of slippage detected exceeds a specified value, the traction control system acts to reduce engine output. At the same time, the auto cruise control adjusts the engine output in order to maintain a preset target vehicle speed.
In other words, while the traction control is required to reduce engine output, the auto cruise control is required, at the same time, to increase engine output when the speed of the vehicle decreases. This means the two systems are sometimes at crossed purposes.
For this reason, in the engine output control devices for vehicles disclosed in Japanese Unexamined Patent Publication No. 3-153426 and Japanese Unexamined Patent Publication No. 3-81541, traction control is executed with priority whenever traction control and auto cruise control are established at the same time.
Also, a method is disclosed in Japanese Unexamined Patent Publication No. 2-201036, whereby a throttle-by-wire control system, a traction control system and an auto cruise control system are integrated to maintain a target engine output torque, this being the common element among those controls, and to select an optimum target engine output torque for each of the various operating modes.
However, with the devices disclosed in Japanese Unexamined Patent Publication No. 3-153426 and Japanese Unexamined Patent Publication No. 3-81541, when traction control is executed and auto cruise control is released, the auto cruise control execution must be re-established when traction control is released. When the vehicle is traveling on a highway and traction control is being executed frequently, re-establishing auto cruise control each time becomes a problem. There is also the problem that during the execution of traction control, auto cruise control cannot be selected.